The present invention relates generally to the field of surface mounting a micro-device and similar such devices and more particularly to surface mounting a micro-device including a package outline which interferes with conventional "flip-chip" surface mounting techniques.
In the field of integrated circuit packaging, surface mount components have become increasingly popular at least in part due to the relatively small footprint which these parts occupy in an overall electronic assembly. Therefore, the use of surface mount components has significantly advanced the continuing goal of miniaturization of electronic assemblies.
One particularly advantageous form used in surface mounting is the "flip-chip" configuration. In this configuration, an integrated circuit chip or die includes a series of bonding pads on an upper surface of the die. Conductive bumps are formed on the bonding pads for supporting and electrically interfacing the die to a separate support member. The die is then inverted and placed on the support member such as, for example, a substrate which includes a pattern of electrically conductive leads arranged for contacting respective ones of the bumps. Once the bumps are in contact with the leads, the material from which the bumps are comprised is caused to flow whereby to form a permanent bond with the substrate. In this way, the die is supported above and does not directly contact the substrate. The semiconductor die used in this configuration is generally of a planar geometry. That is, the upper surface of the die which receives the conductive bumps is generally flat and, in any case, typically resides above and spaced from the confronting support member.
More recently, designers have developed components in the form of micro-devices which do not include the planar geometry of a semiconductor die. One example of such a micro-device is a micro-machined condenser microphone. This microphone includes a bridge structure which forms one immovable "plate" of the condenser (capacitor) while a thin silicon diaphragm forms a movable "plate". The bridge structure is positioned on and extends outwardly a substantial distance from the same surface on which the bonding pads of the microphone are positioned. Surface mounting of this microphone and similar such micro-devices in a flip-chip configuration is difficult to accomplish since the bridge structure interferes with the conventional flip-chip mounting technique described above. However, the present invention provides an assembly, a substrate configured for use in the assembly and an associated method for surface mounting of such micro-devices in a highly advantageous flip-chip configuration.